An alternator regulator may control or regulate the output voltage of an alternator, for example by controlling the current through the coil of the rotor of the alternator. Low-end alternator regulators may output a lamp signal at the dashboard and may provide a Field Monitor (FM) signal, which mirrors the rotor current, to an engine control unit (ECU). High-end alternator regulators may have a communication interface, such as a Local Interconnect Network (LIN), which is a single-wire bus transmitter and receiver, to communicate with the engine control unit.
Both low-end and high-end alternator regulators may be small systems-on-a-chip (SoC). Default parameters may be stored on the chip to match the control characteristics of the alternator regulator to the alternator, the engine and the on-board electrical loads. High-end alternator regulators may provide a non-volatile memory (NVM), such as for example Electrically Erasable Programmable Read-Only Memories (EEPROM, E2PROM), to store the parameters. However, the maximum data rate of 19.2 kbits/s of the UN-interface may lead to unacceptable long times for testing or programming the alternating regulator. For low-end alternator regulators, wire bonding may be used to set the parameters if the alternator regulator is delivered as a bare-die. However, this will not be possible if the alternator regulator is delivered in a package. In this case, it is desired that low-end alternator regulators may also be configured using NVM.
The packages of alternator regulators may have a limited number of pins (or terminals), for example a pin “BA” for battery/alternator voltage, a pin “GND” for ground potential, one or two pins “PH1, PH2” connected to respective coils of the stator of the alternator, a pin “LT” to output a lamp signal, a pin “RVS” for a regulation voltage select, a pin “EXC” to output an excitation current to the rotor coil, and a pin “FM” for the field monitor signal of low-end alternator regulators or a pin “LIN” for the local interconnect network for high-end alternator regulators. For reasons of cost, it is desired to not increase the number of pins.
Because of the small number of pins available, it is not possible to implement a high-speed interface, such as a Controller Area Network (CAN) or a Serial Peripheral Interface Bus (SPI). However, it is desired to provide a fast interface for both low-end and high-end alternator controllers.